Converting siblings to children of a node.

<longdesc>
 <para style="Normal">This is a regular paragraph.</para>
 <para style="Normal">So is this but what follows is a list:</para>
 <para style="LS1">Item one</para>
 <para style="LS1">Item two</para>
 <para style="Normal">This is a regular paragraph.</para>
 <para style="Normal">This is a regular paragraph.</para>
 <para style="Normal">This is a regular paragraph.</para>
 <para style="Normal">What follows is a list:</para>
 <para style="LS1">Item one</para>
 <para style="LS1">Item two</para>
 <para style="LS1">Item three</para>
 <para style="Normal">This is a regular paragraph.</para>
</longdesc>

<p>This is a regular paragraph.</p>
<p>So is this but what follows is a list:</p>
<ul>
  <li>Item one<li>
  <li>Item two<li>
</ul>
<p>This is a regular paragraph.</p>
<p>This is a regular paragraph.</p>
<p>This is a regular paragraph.</p>
<p>What follows is a list:</p>
<ul>
  <li>Item one<li>
  <li>Item two<li>
  <li>Item three<li>
</ul>
<p>This is a regular paragraph.</p>

      <xsl:if test="@style='LS1'">
        <xsl:if test="not(preceding-sibling::para/@style='LS1')">
          <ul>
            <li><xsl:value-of select="."/></li>
        </xsl:if>

<xsl:template match="para[@style='LS1']">
 <xsl:if test="not(preceding-sibling::para[@style='LS1'])">
   <xsl:variable name="node">
     <xsl:copy-of select="."/>
   </xsl:variable>
   <ul>
     <xsl:call-template name="list">
       <xsl:with-param name="listitem" select="$node"/>
     </xsl:call-template>
   </ul>
 </xsl:if>
</xsl:template>

<xsl:template name="list">
 <xsl:param name="listitem"/>
 <li><xsl:value-of select="$listitem"/></li>
 <xsl:if test="following-sibling::para[@style='LS1']">
   <xsl:call-template name="list">
     <xsl:with-param name="listitem">
       <xsl:copy-of select="following-sibling::para"/>
     </xsl:with-param>
   </xsl:call-template>
 </xsl:if>
</xsl:template>